Comfrey Root Poultice — Knitbone, the Ancient Remedy for Sprains and Fractures

Comfrey (Symphytum officinale) has been used to heal broken bones, sprains, and bruises since at least ancient Greece — the Greek physician Dioscorides prescribed it for fractures in the first century CE, and the common name 'knitbone' reflects centuries of use for exactly that purpose. The botanical name itself comes from the Greek 'symphysis' meaning 'growing together'. The plant's extraordinary healing power comes primarily from allantoin, a compound that stimulates cell proliferation and accelerates the growth of new bone, cartilage, and connective tissue. Comfrey root contains far higher concentrations of allantoin than the leaves — up to 0.8% by dry weight. The root also contains rosmarinic acid (a potent anti-inflammatory), mucilage (which soothes and protects damaged tissue), and tannins (which reduce swelling). Comfrey is strictly for external use only — the plant contains pyrrolizidine alkaloids that are toxic to the liver when ingested. As a poultice applied to the skin over sprains, bruises, strains, and simple fractures, comfrey reduces pain and swelling and measurably accelerates healing. Clinical trials published in the journal Phytomedicine have confirmed that comfrey root extract reduces ankle sprain healing time by several days compared to placebo.